1. Combine topping ingredients in an electric mixer and mix until crumbly and pea-sized pieces form, about 3-5 minutes. Do not over-mix. Set aside.
2. In small bowl combine sugar and cornstarch until well-mixed. In separate mixing bowl, combine grapes and blackberries. Sprinkle sugar and cornstarch over fruit and toss to coat. Place into greased 8” square baking dish. Sprinkle crumb topping over fruit, coating evenly. Place pan in oven and bake for 40-45 minutes until top is golden and fruit is bubbling around the edges. Serve warm as it or with whipped cream or ice cream.
3. This can also be baked in individual ramekins for a more elegant presentation. Bake time will be shortened to 25-30 minutes.

*Note: Old fashioned or quick oats may be used.